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Hesperornitheans
Hesperornithes is an extinct and highly specialized group of aquatic avialans closely related to the ancestors of modern birds. They inhabited both marine and freshwater habitats in the Northern Hemisphere, and include genera such as ''Hesperornis'', ''Parahesperornis'', ''Baptornis'', ''Enaliornis'', and ''Potamornis'', all strong-swimming, predatory divers. Many of the species most specialized for swimming were completely flightless. The largest known hesperornithean, ''Canadaga arctica'', may have reached a maximum adult length of . Hesperornitheans were the only Mesozoic avialans to colonize the oceans. They were wiped out in the Cretaceous–Paleogene extinction event, along with enantiornitheans and all other non-avian dinosaurs, and many other diverse plant and animal groups. Anatomy and ecology Most of what is known about this group rests on analyses of single species, as few provide sufficiently complete fossils for analysis. Although some of the smaller and more basal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asiahesperornis
''Asiahesperornis'' is a prehistoric foot-propelled diving toothed flightless bird genus from the Late Cretaceous. The single known species is ''Asiahesperornis bazhanovi''. It lived in what today is Kazakhstan, at its time the shores of the shallow Turgai Sea. It was a member of the Hesperornithes, flightless toothed seabirds of the Cretaceous. Its exact relationships are not completely resolved, but it probably belongs into the Hesperornithidae just like ''Hesperornis'', well known from the Western Interior Seaway that covered most of the US Midwest in the Mesozoic. Its name is derived from its findings in Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area .... References Bird genera Extinct flightless birds Fossil taxa described in 1991 Hesperornitheans Late Cretaceo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pasquiaornis
''Pasquiaornis'' is a prehistoric flightless bird genus from the Late Cretaceous. It lived during the late Cenomanian, between 95 and 93 million years ago in North America.Tokaryk, Cumbaa and Storer, 1997. Early Late Cretaceous birds from Saskatchewan, Canada: the oldest diverse avifauna known from North America. Journal of Vertebrate Paleontology. 17(1), 172-176. Two species have been described, ''P. hardiei'' and ''P. tankei''. The genus ''Pasquiaornis'' was a member of the Hesperornithes, flightless toothed seabirds of the Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th .... Though its relationships to other members of this group are inadequately known, ''Pasquiaornis'' appears to have been one of the more basal lineages. (2004): The Theropod DatabasePhylogeny of tax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parahesperornis
''Parahesperornis'' is a genus of prehistoric flightless birds from the Late Cretaceous. Its range in space and time may have been extensive, but its remains are rather few and far between, at least compared with its contemporary relatives in ''Hesperornis''. Remains are known from central North America, namely the former shallows of the Western Interior Seaway in Kansas. Found only in the upper Niobrara Chalk, these are from around the Coniacian-Santonian boundary, 85-82 million years ago (mya). ''Parahesperornis alexi'' (Martin, 1984) was long lumped with specimen YPM 1478, described initially as ''Hesperornis gracilis'' and later moved to the monotypic genus ''Hargeria'' (Lucas, 1903). It then turned out that this genus' description actually referred to specimen KUVP 2287, which eventually became the holotype of ''P. alexi''. Nonetheless, the taxon description of ''Hargeria'' was about ''"Hesperornis" gracilis'' exclusively, and thus despite the misidentification it applies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hesperornis
''Hesperornis'' (meaning "western bird") is a genus of cormorant-like bird that spanned the first half of the Campanian age of the Late Cretaceous period (83.5–78 mya). One of the lesser-known discoveries of the paleontologist O. C. Marsh in the late 19th century Bone Wars, it was an early find in the history of avian paleontology. Locations for ''Hesperornis'' fossils include the Late Cretaceous marine limestones from Kansas and the marine shales from Canada. Nine species are recognised, eight of which have been recovered from rocks in North America and one from Russia. Description ''Hesperornis'' was a large bird, reaching up to in length. It had virtually no wings, and swam with its powerful hind legs. Studies on the feet initially indicated that ''Hesperornis'' and kin had lobed toes similar to modern-day grebes, as opposed to webbed toes as seen in most aquatic birds such as loons. More recent work looking at the morphometrics of the feet in hesperornithiformes and mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fumicollis
''Fumicollis'' is a genus of prehistoric flightless birds from the Late Cretaceous (Coniacian-Santonian) Niobrara Chalk of Kansas. Description Diagnostic traits of ''Fumicollis'' include presacral vertebrae with expanded ventral processes, an elongate pelvis with reduced acetabulum (acetabulum width: pelvis length is approximately 0.096 meters), a femur with expanded lateral condyle (transverse extent of condyle over 75% of midshaft width) and moderately expanded trochanter. The genus name refers to the Smoky Hill Chalk Member of the Niobrara Chalk in which it was found.Bell A, Chiappe LM (2015) Identification of a New Hesperornithiform from the Cretaceous Niobrara Chalk and Implications for Ecologic Diversity among Early Diving Birds. PLoS ONE 10(11): e0141690. https://doi.org/10.1371/journal.pone.0141690 Discovery The holotype of ''Fumicollis'', USNM 20030, was found by Harold Shepherd and George Sternberg in 1937 in the Smoky Hill Member of the Niobrara Chalk of Logan County, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canadaga
''Canadaga'' (meaning "Canadian bird") is a flightless bird genus from the Late Cretaceous. The single known species is ''Canadaga arctica''. It lived in the shallow seas around what today is Bylot Island in Nunavut, Canada. Its fossils were found in rocks dated to the mid-Maastrichtian age, about 67 million years ago. It was a member of the Hesperornithes, flightless toothed seabirds of the Cretaceous. Among these, it belonged to the Hesperornithidae, along with ''Hesperornis'', the well-known namesake genus. ''C. arctica'' is one of the largest known members of the Hesperornithes, reaching a length of . It also represents one of the last known members of the lineage.Holtz, Thomas R. Jr. (2008) ''Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages'Winter 2010 Supplementary Information Unlike its relatives which are mainly known from subtropical or tropical waters, this species seems to have ranged in temperate or even subarctic areas. The sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hesperornis BW (white Background)
''Hesperornis'' (meaning "western bird") is a genus of cormorant-like bird that spanned the first half of the Campanian age of the Late Cretaceous period (83.5–78 mya). One of the lesser-known discoveries of the paleontologist O. C. Marsh in the late 19th century Bone Wars, it was an early find in the history of avian paleontology. Locations for ''Hesperornis'' fossils include the Late Cretaceous marine limestones from Kansas and the marine shales from Canada. Nine species are recognised, eight of which have been recovered from rocks in North America and one from Russia. Description ''Hesperornis'' was a large bird, reaching up to in length. It had virtually no wings, and swam with its powerful hind legs. Studies on the feet initially indicated that ''Hesperornis'' and kin had lobed toes similar to modern-day grebes, as opposed to webbed toes as seen in most aquatic birds such as loons. More recent work looking at the morphometrics of the feet in hesperornithiformes and mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potamornis
''Potamornis'' is a prehistoric bird genus that dated back to the late Maastrichtian age of the late Cretaceous period. Its scrappy remains were found in the Lance Formation at Buck Creek, USA, and additional possible remains were found in the upper Hell Creek Formation of Montana, dated to the Danian age of the Paleogene period, though these may have been reworked. A single species was named and described in 2001: ''Potamornis skutchi''. This was almost certainly a member of the Hesperornithes, the hefty and toothed flightless diving birds of the Mesozoic seas. Its precise relationships are not all too clear; the quadrate bone is unique in some respects but apparently shares more apomorphies with the family Hesperornithidae - the "typical" Hesperornithes - in cladistic analysis.Mortimer (2004) Consequently, it might be considered a fossil hesperornithid with a different feeding specialization. Though it was heavily built like many (flying and flightless) diving birds, it weighe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Judinornis
''Judinornis'' is a genus of prehistoric flightless birds from the late Cretaceous period. The single known species is ''Judinornis nogontsavensis''. Its fossils have been found in Nemegt Formation rocks of southern Mongolia, and though the age of these deposits is not fully resolved, ''Judinornis'' probably lived some 70 million years ago during the early Maastrichtian. The Nemegt Formation does not seem to contain marine sediments. Consequently, and unlike its relatives, this was apparently a bird of estuaries and rivers running from the mountains thrown up by the Cimmerian orogeny through the arid lands of continental East Asia towards the Turgai Sea and the former Shigatze Ocean. ''Judinornis'' was a member of the Hesperornithes, flightless toothed seabirds of the Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enaliornis
''Enaliornis'' is a genus of hesperornithine birds which lived in the early Late Cretaceous, making them the oldest known hesperornithines. Fossils have been found near Cambridge, England. Due to its lack of certain hesperornithid apomorphies, they were much more "conventional" birds and were initially held to be Gaviiformes (loons/divers). Description Based on the remnants that have been studied, it has not been determined if these birds had teeth like the others from this order. However, they were believed to not have well-developed wings. Like other hesperornithines, they probably had lobed feet for swimming, rather than webbed feet.Lim, J. D., Zhou, Z., Martin, L. D., Baek, K. S., & Yang, S. Y. (2000). The oldest known tracks of web-footed birds from the Lower Cretaceous of South Korea. ''Naturwissenschaften'', 87(6), 256-259. Classification ''Enaliornis'' was originally named ''Pelagornis'' ("sea bird") by Seeley in 1866, but that name was preoccupied by a Miocene bird rel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chupkaornis
''Chupkaornis'' is a genus of prehistoric flightless birds from the Late Cretaceous (Coniacian-Santonian) Kashima Formation of Hokkaido, Japan. Description Diagnostic traits of ''Chupkaornis'' include a finger-like projected tibiofibular crest of femur, deep, emarginated lateral excavation with a sharply defined edge of the ventral margin of the thoracic vertebrae, and the heterocoelous articular surface of the thoracic vertebrae.Tomonori Tanaka, Yoshitsugu Kobayashi, Ken'ichi Kurihara, Anthony R. Fiorillo and Manabu Kano. 2017. The Oldest Asian Hesperornithiform from the Upper Cretaceous of Japan, and the Phylogenetic Reassessment of Hesperornithiformes. Journal of Systematic Palaeontology. Phylogeny ''Chupkaornis'' is recovered by Tanaka et al. (2017) as more derived than the Cenomanian-age form ''Pasquiaornis'', but less advanced than ''Brodavis'' and ''Baptornis ''Baptornis'' ("diving bird") is a genus of flightless, aquatic birds from the Late Cretaceous, some 87-80 mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enaliornithidae
''Enaliornis'' is a genus of hesperornithine birds which lived in the early Late Cretaceous, making them the oldest known hesperornithines. Fossils have been found near Cambridge, England. Due to its lack of certain hesperornithid apomorphies, they were much more "conventional" birds and were initially held to be Gaviiformes (loons/divers). Description Based on the remnants that have been studied, it has not been determined if these birds had teeth like the others from this order. However, they were believed to not have well-developed wings. Like other hesperornithines, they probably had lobed feet for swimming, rather than webbed feet.Lim, J. D., Zhou, Z., Martin, L. D., Baek, K. S., & Yang, S. Y. (2000). The oldest known tracks of web-footed birds from the Lower Cretaceous of South Korea. ''Naturwissenschaften'', 87(6), 256-259. Classification ''Enaliornis'' was originally named ''Pelagornis'' ("sea bird") by Seeley in 1866, but that name was preoccupied by a Miocene bird rela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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